In the present invention, a content distribution server distributes a content key, encrypted content encrypted using the content key, and playback control information describing a playback mode restriction for a specific section of content, to a content playback terminal, and the content playback terminal refers to the playback control information, and decodes and plays back encrypted content in the case of a playback mode in which the specific section of content is not restricted. By this means, the playback mode of a specific section of content can be restricted based on playback control information.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A content playback control method, comprising: storing in a memory, information describing: license information including a content key and a usage condition; special sections subject to a restriction of a special playback of content, the special sections being received separately from the license information; and a playback mode permitted in each of the special sections, the usage condition specifying whether a playback is performed with respect to the special sections and the playback mode, the usage condition and at least one of the special sections and the playback mode correspond to identification information so that an issuer can set a plurality of the special sections or the playback mode using the identification information, and the identification information attached to the license information for encrypted content and playback control information; decoding encrypted content using the content key to generate decoded content, only when the usage condition is met; determining, when an instructed special playback of the decoded content is performed and the usage condition specifies the special sections of the decoded content described in the information stored in the memory, whether the special sections of the decoded content described in the information stored in the memory include a point at which the instructed special playback is performed; and controlling the instructed special playback for the decoded content, when the special sections include the point at which the instructed special playback is performed, and when the usage condition specifies that the playback is performed based on the playback mode described in the information stored in the memory, and a playback mode of the instructed special playback corresponds to one of the playback mode described in the information stored in the memory.
2. The content playback control method according to claim 1 , wherein the special playback comprises at least one of forward, rewind, skip and jump.
3. The content playback control method according to claim 1 , wherein the restriction of the special playback is described by a possibility/impossibility code.
4. The content playback control method according to claim 1 , wherein each of special sections are described on a per segment basis.
5. The content playback control method according to claim 1 , wherein the license information manages the content key and the usage condition as a pair.
6. The content playback control method according to claim 1 , wherein the usage condition is protected from unauthorized duplication or tampering by using DRM technology.
7. The content playback control method according to claim 1 , wherein an ID is attached to the license information and playback control information for encrypted content.
8. The content playback control method according to claim 1 , wherein the license information is received by a communication directed to a specified recipient, and the special sections are received by broadcast.
9. The content playback control method according to claim 1 , wherein the identification information is an identification of an issuer.
10. A content playback control terminal, comprising: a memory that stores information comprising: license information including a content key and a usage condition; special sections subject to a restriction of a special playback of content, the special sections being received separately from the license information; and a playback mode permitted in each of the special sections; the usage condition specifying whether a playback is performed with respect to the special sections and the playback mode, the usage condition and at least one of the special sections and the playback mode correspond to identification information so that an issuer can set a plurality of the special sections or the playback mode using the identification information, and the identification information attached to the license information for encrypted content and playback control information; a content decoder that decodes encrypted content using the content key to generate decoded content; a license information processor that passes the content key to the content decoder, only when the usage condition is met; and a playback control information processor that controls the playback of the content in the content decoder based on the special section and the playback mode permitted in each of the special sections, wherein: when an instructed special playback of the decoded content is performed and the usage condition specifies the special sections of the decoded content described in the information stored in the memory, the playback control information processor determines, whether the special sections of the decoded content in the information stored in the memory include a point at which the special playback is performed, and when the special sections include the point at which the instructed special playback is performed, and when the usage condition specifies that the playback is performed based on the playback mode described in the information stored in the memory, and a playback mode of the instructed special playback corresponds to the playback mode described in the information stored in the memory, the playback control information processor controls the instructed special playback for the decoded content.
11. The content playback control terminal according to claim 10 , wherein the special playback comprises at least one of forward, rewind, skip and jump.
12. The content playback control terminal according to claim 10 , wherein the restriction of the special playback is described by a possibility/impossibility code.
13. The content playback control terminal according to claim 10 , wherein each of special section is described on a per-segment basis.
14. The content playback control terminal according to claim 10 , wherein the usage condition is protected from unauthorized duplication or tampering by using DRM technology.
15. The content playback control terminal according to claim 10 , wherein an ID is attached to the license information and playback control information for encrypted content.
16. The content playback control terminal according to claim 10 , wherein the license information is received by a communication directed to a specified recipient, and the special sections are received by broadcast.
17. The content playback control terminal according to claim 10 , wherein the identification information is an identification of an issuer.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 19, 2011
April 21, 2015
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